<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>






<div>
    <p>半径</p>
    <input type="text" placeholder="半径" id="a">
</div>

<div>
 <p>周长</p>   <input type="text" placeholder="周长" id="b">
</div>

<div>
    <p>面积</p> <input type="text" placeholder="面积" id="c">

</div>


<script src="JavaScript.js">

</script>
</body>
</html>